The Sky’s Greatest Show

While these are the shortest nights of the year, many a fond memory is set star-gazing on warm summer evenings. And in between the bursts of flame and the clouds of smoke honoring our independence this week, Friday’s new moon provides a dark backdrop highlighting the greatest show in the heavens.
    One of the first lights to appear after sunset, around 8:35, is likely Arcturus almost directly overhead. The brightest star visible and fourth-brightest overall, Arcturus edges westward, finally setting in the northwest around 4am.
    The next light you’re likely to emerge from twilight’s glow is Saturn high in the southwest. The ringed planet shines a steady yellow compared to twinkling Arcturus. By 1am, Saturn sets due west.
    You’ll need sharp eyes, good timing and a clear view of the west horizon just after sunset if you hope to spot the only other visible evening planet, Mercury. Within an hour of sunset, look to the point where the sun sets in the west-northwest and scan the horizon for a surprisingly bright glow. Shining near magnitude –1, Mercury is more than twice as bright as Saturn and is in fact outdone by only Venus, Jupiter and a few stars.
    Immediately after sunset the night of the 30th, look for Mercury aligned with the stars Pollux and Castor. They’ll be low in the sky, with Mercury 15 degrees above the northwest horizon, Pollux a little more to the north and Castor more northward still. Binoculars should help pick them out of twilight’s haze.
    Sunday, a nascent crescent moon joins Mercury low in west during dusk. While the waxing moon moves onward, Mercury maintains this western evening perch for much of July.
    Jupiter rises in the northeast around 2am, followed a couple hours later by Mars. Venus crests the horizon barely a half-hour before sunrise, around 5:45.